Switch apparatus for use with telephonic receivers



Feb. 21,-:1928.

E. A. GRAHAM SWITCH APPARATUS FOR USE WITH TELEPHONIG RECEIVERS 3 Sheets-Sheet 1 m 40 n 6 w Q mfi mw fim m. w/@ m] Q @4 0 q W Q5@+@ NJ F Q 0 a Q g m w j Inventor" 5m Qfiedsfimm y M M Feb. 21, 1928.

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. E. A. GRAHAM SWITCH APPARATUS F01: USE WITH TELEPHONIC RECEIVERS Filed Feb. 18. 1926 3 Sheets-Sheet 5 g, 5/5 1 Inventor 6m I series oi? Patented Feb. 21, 1928.

stares nnwnnn earner) cn win, or :BRocKnEY, Lennon,- ENGLAND;

fXE-GU'EQRS or 'SAED nnwnn-n ALFRRCQ ALFRED GRAI'IAI PATENT 1 ossice.

MARIA GRAHAM AND BE, DECEASED.

.SW ITCH APZPARATUS'EOR WITH TEII'EPHONIC BECEIVERS.

application filed February 18, 1926, serial No.

ii hen a loud speaking telephone is to be used in conjimction with a niiiltiwalve wireless in the pla e circuit of:

A es,,conniio 'i'lOfi S through the telephone windings. 'lliider some circumstances, where for instance. the actual ,.plate current-.isQhigh in value, such being panti ularly the case when power valves" are .em-

ployed torus-e in low frequency amplification, it is advantageous to. provide a shunt path for the continuous current component so that only the fiuctuatory Component, alter-f nating in character, flows in the telephone windings. For thispuipose, it ,is common practice to incorporatein the output leads of a wireless receiving set, a series f ,connec tions known .as a filtericircuit, which pro vides a choke coil or inductance directly 1 cross the output terminals, the said choke coil or inductance being bridged by the telephonic windings in series with condenser of appropriate capacity, .so as in effect to allow only the modulated telephonic current to pass through to the telephone receiver or receivers and toiilter off the steady direct cuiti'cnt .COlHpOX-IGD B thcreirom, Such lilter circuits and their application are generally well known and no claim is herein made to the use per seof such a circuit.

This invention has for its object to pr.0-. vide means whereby may be tested or compared, relative to eachother, or to one,

which may be .a standard, alnurn'bei' of telephonic receivers adapted collectively or singly to be connected in circuit with any one of a number of wirelessreceiving sets in the output leads of which may or may not be incorporated a filter circuit adapted for the purpose ,hereinbetore stated. A further object of the invention is to provide an improved switching arrangement or apparatus for use with a filter circuit, whereby the telephonic current can be ap plied to one, or to a number of telephonic receivers, which advantageously may be of the loud speaker type, and whereby also the filter circuit is .or can be switched into or out-tot circuit at will.

To this end, switch apparatus according to the invention comprises a frame or holder adapted to house there'injt'he capacity and receiving}; set, the steady current flowing the last valve oi? al 89,180,, and in .Great Britain September 7, 1925.

means, one of the bounding planes of said frame or holder, constituting a panel, being made of'insulati-ng-material adaptedto carry all or most of the component parts, includ- 'ing the necessary switches, teriiiinals and wiring, to enable the object of the invention to be attained in a simple and effective manner.

In the accompanying drawings, Fig. l is a plan of one construction of switch appara- ,tus according to the invention. Fig. 2 is an shown in Fig. 2, the switch being shown in its mid or of? position in 'both lfig'ui es.

Figs. 6 and? are underside views ofjth said switch in two opposite closed positions. Fig. 8 shows, diagrammatically, a modified construction of the switch apparatus. 7

According; .to'the example shown in Figs. 1 ,to '6 inclusive, the frame orfliolder'ior the assembly of the pants mentioned," comprises a box 1 haying-side walls and .a bottom of 3 shows partly in vertical 7 wood, and a top or closure Qmade ofebonite adapted to be detachablysecured to thebox, as by screws ,-2:, and; constituting a panel to the underside of whichis attached achokecoil 3 and a, condenser, for the filter circuit, and also the contact .inembersof' switching means, together with the wiring tor connecting the various parts in proper relationship, so that when such a panel is secured to the box, the said parts carried thereby will be situated within the box except parts of the switch operating levers. On the out-. ,side [of the panel are mounted terminals for connection to the output leads from a wireless set .or sets and also pairs of terminals for theconneetion of telephone leads. In the example shown, there :are two ,pairs of terminals 55 and 6 6? for connection -to the cutput'leads of two wirelesssetsand six pairs o'i'terminals'Z, 7 for connection to six pairs of telephone receivers. Extending through slots 8 :in the panel 2 and pivoted inbearings 9 carried by the panel, are. a number let switch-levers 10 for operating the circuit making and breaking contacts of switches located within the box.

These switches, for controlling thecircuit of telephone receivers, connected across the v material, as for instance ebonite, the arrangement being such that when the inner end 10 of the corresponding switch lever 10, which is of conducting material and forms a movable contact, is in its off-position, that is to say, when it is intended that it shall not complete a circuit controlled thereby, it is touching the free end, of the longer spring finger 12 only, as shown in full lines in Fig. 2, but when it is desired to complete the circuit, it can be moved through an angle, in a plane perpendicular to that of the panel 2, by means or the lever handle 10 situated outside the box, and be brought as shown in dotted lines in Fig. 2, into 'contactwith both ofthe'spring fingers 11 and 12 between which it is arranged to work. The other end 11 01 the spring member 11, is connected to the inwardly projecting stemof one, namely 7, of one of the pairs of terminals 7--7 on the outside of thepanel 2 and the other end 12 of the spring member 12 is connected to an inner I conducting wire 13 which is common to all the telephone switches. Such a telephone switch is secured to the underside of the panel 2, as by a screwed stem 2 secured to the panel 2 and extending in a downward direction and passing through the centre of the two ebonite discs 1d between which the spring wire members 11, 12 are firmly clamped by screwing a nut 2 on the screw..

In order that the spring members11-12 may take a snug and secure seating between the discs and in order to prevent them touching each other, or the screw 2 extending between them, one disc may shown in Fig. 4, be formed on its clamping surface with two substantially semi-circular opposed grooves M -14 of a depth sutficient to admit of the housing of the said wire members and yet ensuring a firm clamp. The other terminal 7 of the pair of terminals 77 for each switch is connected to another inner conducting wire 15 common to them and connected to the other main terminal 5? of the switch apparatus.

The mounting of the switch levers 10 may be effected by providing each of them at an intermediate portion of its length with a cross pin 10 (Fig. 3) pivotally mounted between a metal plate 16 and the underside of thein'sulating panel 2 which is notched at 17 to accommodate the ends of the said pin. The panel may have inscribed thereon directions for moving the lever in order to make'or break circuit.

A telephonic receiver can be connected across the pair of terminals 7, 7 corresponding to any of the switches by means of which the said receiver can be put in and 18 19 and 20 clamped between two plates 24 of ebonite by means of a screw 25 and' nut 26, like the two spring wire members 11 and 12 for each telephonic switch hereinbefore described. {These stationary spring contact members are connected up in the manner hereinafter described.

As in the example. now being described,

two pairs of terminals 5, 5 and 6-6? are.

provided for connection to two separate wireless sets, either of which can be used at will, interchanging switch mechanism is necessary whereby either of the wireless sets can be switched into use at will. Conveniently, a single interchanging switch may be used "for the purpose. In the example shown in Figs. 2, 5, 6 and 7, the interchanging I switch comprises two relatively short sta .tlonary upper spring contacts 27 and 27 each having a bent free end, two longer stationary lower spring contacts 28 and 28 each having a bent free end, two relatively long stationary upper spring contacts 29, 29" and two insulated coaxially' arranged cylindrical movable contacts 30 and 30 The stationary contacts are clamped between three discs 32 of insulating material for instance ebonite,

in such manner that they are insulated front one another. The movable contacts 30 and 30 are carried by but insulated from a lever 31 pivoted to the panel 2 and extending f throughland above the same. 28 and 29 are arranged to co-act with the movable contact 30, and contacts 27 28 and Contacts 27 29 are arranged to coact with the movable" is connected to one pole 45" of the condenser 4: and to the contact 18 of the'control switch 7 and contact 29 is connected to the conductor 15 to which the terminals are connected,

and toone terminal 3 of the choke coil 3.

Contact 19 of the control switch is connected to the conductor 13 to, which the contacts 12 ofthe several telephonic switches are,con-.

nectedand also to the pole 4 of the condenser 1.

Contact 20 or" the control switch is'connected to thesecon-d terminal 3 of. the

l/Vir'th the movable contact .21 inchoke 'coil. the position shown in full :line in Fig. 2, namely-between contacts18 and 19 the condenser 4 is short circuited and the circuit of the-choke coil is open so that both of these devices are then out of use. When the movableicontact 21 is movedinto the position shown in dotted lines inwhich it isbetween contacts 1-8 and 20, the condenser 4: is connected in series with the-conductor 13, one or more of the telephone switches 10,11, 12,,

one or more telephones connected across-one or morepairs of terminals: 7 7 and condue tor 15, this circuit being connected across one or other of the pairs of terminals .5, 5 or 6, 6 or losing open. vVV'ith the. lever 31-01? the interchanging switch in the mid or oil position shownin Figs. 2 and 5, contacts 29 and 29 alonebear on the movable contacts 30 and: 30 so that bothsets of terminals 5, V

5 and 6, 6 are electrically disconnected from the rest of the apparatus. VV-hen the lever 31, of the interchanging switch moves the contacts 30, 30 into the posit-ion shown in F ig. 6, contact ZTbea-rs on contact .30 upon which contact 29 simultaneously bears, and

! Which contact '29 simultaneously bears, and

contact ;28 bears on contact 30 =upon which contact. 29 simultaneously bears, so :that the telephone switches and terminals 7 are then connected across the second :set of terminals 6 6 i I In the:modiifiedconstruction shown in Fig.

- 8, only one set of terminals 5, 5 is provided so that no interchanging switch is necessary. In this, the-contact 18 of the control switch is connected to thetermi-nalb and to one pole 4 of the condenser at the other pole 4 of which is conneotechto the conductor 13. The contact 19 is connected =to one terminal 3 i the '(I lIOkQ'COll .8 the other terminal-3 of which is connected to the terminal to which is also connected the conductor to,

- b8111 ada ted to .connect'oneiorother of the pairs =of Wireless terminals tout-he circuits which :the terminals 7 are connected. Gontact 20 is connected-direct to the conductor 13 to which the contacts 12 of the telephone 'S\VllICl16S 10, ,11, 12 are connected. WWien the :movable contact 21 is moved into the position, shown in full lines, the choke coil -3 and condenser .are connected for use, and when it is moved into the position shown in dot-ted lines, the choke coiland condenser are put OutfOf use. p p

The terminals 7., :7 mounted ontheoutside of the panel 2 may be connected to the conducting wires13-and 15 within the box -1 by soldering their stems, whichextend through the panel, :to the desired 13 and .15.

points f thev wires For the sake "ofweasy distinction, the, ter- I Iminals 7,17 are referred to (in theclaims as telephone terminals, and the term1nals5f eand 66 are, for a like reason, reterred to :in

the claims 'as Wireless terminals.

WV'hat I claim is 1. Switch apparatus for fuse with telephonic receivers. and wireless apparatus,

comprising a support, pairs :ofQi-nsu-lated telephone terminals :canried thereby, an an- ,sulated pair of wireless terminals carried by said support, a choke coil, acondenser,

telephone switches and a control SWltChgBfliClT telephone 1 switch -being adapted .to wolose and open a ci'rcuit between :the":palii1- f0f' wireless terminal-s through a telephonic receiver con nected to the correspondingpairo'f :telephone terminals and the control .switchebek ing adapted in one position towcon-neot the choke coil across the pair :of W'lI'QlQSSiEBIIHlnals and. connect the condenser in. semes .ci-r cult with each telephone circurtclosedqby a telephone switch and inanother-position .to-

put the choke ,coil and condenserqout of iuse and enable each telephone circuit to hceconnected acrossthe pair of wireless terminals.

2-. Switch apparatus tEor. use. with 616 phonic receivers and" Wireless. apparatus,

comprising :a support, pairs of insulated telephone terminals caTn-iedkthereby, pairs of insulated wireless terminals camried by said support, for connection to independent wireless sets, a choke-coil, a condenser.,,. telephone switches,- acont-rol switch and. inter- I changing switch means, each telephone switchbeing adapted to close {and 28.4 11- cuit between one orother ipairaof wineless 'terminalsnand a "-il'LQlBPhQIllC' receiver, con- 'nected to the conresponding. pair of telephone -tenminals, the control switch .being adapted in one position to connect the choke coil'acrossrone orsother of the :pairs of wirelessfiterminals andv place the condenser in. each"telephonecircuit closed by a telephone switch and in another position ,to put the choke coil andcondenser out oat actionand enable-each telephone circu t to .he i connected across one -01?" the pairs of wireless terminals and the-interchanging switch means controlled hythe telephone switches and control switch.

Switch ;apparatus-for .use with telephonic receivers and wireless apparatus,

comprising a. support, pairs o-f'insulated telephone terminals carried thereby, a pair -01": insnlated wire'lessterminals :canr-ied by said support, conducting nae-ans. -between one of the terminals of each pair of telephone Jlll the second terminal of a pair of telephone terminals to said conductor, a choke coil, a condenser, and a control switch adapted in one position to connect the choke coilacross the pair of wireless terminals and the condenser in circuit between the second wireless terminal and said conduct-or and in another position to connect said conductor to the second wireless terminal and to put the choke coil and condenser out of action.

4:. Switch apparatus for use with telephonic receivers and wireless apparatus, comprising a support, pairs of insulated telephone terminals carried thereby, a pair of insulated wireless tern'iinals carriedby said support, conducting means bet-ween one of the terminals of each pair of telephone terminals for connection to one of the wireless terminals, a conductor, a plurality of telephone switches each adapted to connect the second terminal of a pair of telephone terminals to said conductor, a choke coil connected at one end tothe first mentionedwireless terminal, a condenser having one pole connected to said conductor and a control switch comprising three stationary con tacts and a movable contact, one of the stationary contacts being connected to the second wireless terminal and to the second pole of the condenser, another ot the stationary contacts being connected to the second end of the choke coil and the third stationary contact being connected to said conductor, the movable contact in one position closing a circuit between the first and secondly mentioned stationary'contacts and leaving open a circuit between the first and third stationary contacts and in another position'opening the circuit between the first and second stationary contacts and closing a c1rcu1t between the first and third contacts. 7

5. Switch apparatus for use with telephonic receivers and wireless receiving apparatus, comprising a support, a panel of insulating material carried by said support, a plurality of repairs of telephone terminals secured to said panel and external thereto, a pair 0t wireless terminals secured to said panel and exterior thereto, a conductor connected to one of the telephone terminals of each palr thereof and adapted to be connected to one of the wireless terminals, a plurality of telephone ,switches secured to the inner side of said panel and each having two stationary contacts and a movable contact, one of the.

stationary contacts being connected to the second terminal of a correspondingpair of telephone terminals, a second conductor connected to the second stationary contact of each of the telephone switches and adapted to be connected to the other wireless termi-'v nal, levers extending through and pivoted to the panel and each carrying the movable contact of one of the telephonicswitches, a choke coil and a condenser, and a control switch adapted in one position to connect the choke coil across the pair of wireless terminals and the condenser 1n circuit between the second wirelessterminal and the: said second conductor and n another position to connect said second conductor direct to said second wireless terminal and to put the choke coil and condenser out of action, said control switch being secured to the inner side of the panel and having an operating lever extending through the panel to the plurality of pairs of telephone terminals se-.

cured to said panel and external thereto, a pair Of-WllGlBSS terminals secured to sa d panel and exterior thereto, a conductor connected to one or the telephone terminals of each pair thereof and adapted to be connected to one of the wireless,terminals, afiplurality of telephone switches secured to the inner side of said panel and each having two stationary contacts and a mov'-' able contact, one of the stationary contacts being connected to the second terminal of a corresponding pair of telephone terminals, a second conductor connected to the. second stationary contact of each of the tele phone switches and adapted to be connected to the other wireless terminal, levers eX- tending through and pivoted to the panel and each carrying the movable contact of one of the telephonic switches, a choke coil having one end connected to the wireless terminal to which the first mentioned con ductor is connected, a condenser having one pole connected to the secondly mentioned; conductor, and a control switch secured to the inner side of said paneland comprising three stationary contacts, a movable contact and an operating lever extending through said panel to the exterior thereof, one of the stationary contacts ofthe said control switch serving for connection to the second wireless terminal of a pair thereof and to one-pole or" the condenser, another of the said stationary contacts serving for connection to the second end of the choke coil and the third stationary contact being connected to the secondly mentioned conductor. i

7. Switch apparatus for use with telephonic receivers and wireless receiving apparatus, comprising a support, a panel of insulating'material carried by said support,

a plurality of pairs of telephone terminals i secured to said panel and external thereto, pairs of wireless terminals secured to said panel and external thereto, a conductor connected to one of the telephone terminals of each pair thereof, a plurality of telephone switches secured to the inner side of said panel and each having two stationary contacts and a movable contact, one of the stationary contacts being connected to the second terminal of a corresponding pair of telephone terminals, a second conductor connected to the second stationary contact of each of the telephone switches, levers extending through and pivoted to the panel and each carrying the movable contact of one of the telephone switches, a choke coil hav ing one end connected to the first mentioned conductor, a condenser having one pole connected to the secondly mentioned conductor, a control switch secured to the inner side of said panel and comprising three stationary contacts, a movable contact and an operating nected to the other end of the choke coil and the third stationary contact being connected to the secondly mentioned conductor, and in 'terchanging switch mechanism whereby the.

telephone switches and associated parts can be connected across either pair of wireless terminals at will.

Signed at London, England, this eleventh day of January, 1926. v EDWARD ALFRED GRAHAM. 

